Expansion plate

ABSTRACT

An expansion plate or sheet comprises a plurality of panels in sealed side-by-side relation, each panel including a sheet, or sheets, which extend continuously substantially the full distance between two adjacent walls for connection in air-tight relationship therewith and most of said panels include at least one elongated depression therein which extends much of the distance between the two adjacent walls.

United States Patent [191 Round et al.

[ Feb. 26, 1974 EXPANSION PLATE Inventors: Byron Joseph Round, Simsbury;

Eizens Abolins, Windsor, both of Conn.

Combustion Engineering, Inc., Windsor, Conn,

Filed: Dec. 26, 1972 Appl. No.: 318,332

Assignee:

US. Cl 122/6 A, 122/494, 122/510 Int. Cl. F22b 37/24 Field of Search122/6 A, 235 A, 235 G, 494,

References Cited UNITED STATES PATENTS 5/1945 Foresman 122/235 3,310,0383/l967 Kuchelbacher 122/494 3,364,905 l/1968 Jordan 122/494 3,402,7009/1968 Brunner 122/6 3,407,788 10/1968 Hagmann.... 122/6 3,592,1717/1971 Bernstein 122/494 Primary Examiner-Kenneth W. Sprague Attorney,Agent, or FirmStephen A. Schneeberger [5 7] ABSTRACT An expansion plateor sheet comprises a plurality of panels in sealed side-by-siderelation, each panel including a sheet, or sheets, which extendcontinuously substantially the full distance between two adjacent wallsfor connection in airtight relationship therewith and most of saidpanels include at least one elongated depression therein which extendsmuch of the distance between the two adjacent walls.

6 Claims, 6 Drawing Figures EXPANSION PLATE BACKGROUND OF THE DISCLOSUREThis invention relates to an expansion joint and more particularly to anair-tight connection between two adjacent members subject to differentoperating temperatures and hence to different changes in physicaldimensions.

A problem has existed in providing a fluid-tight connection between twoadjacent members subject to different operating temperatures and henceto different amounts of expansion, particularly where it is impracticalto use slip joints or packings. This problem is particularly acute inlarge vapor generators in which there may be temperature differences ofseveral hundred degrees F. between adjacent surfaces, such as between asteam header or fluid cooled ring pipe or header and an adjacentuncooled ash hopper through which combustion gases are directed. Becauseof the large size of the steam generators now being considered, and thehigh temperatures at which they operate, the differences in expansionbetween adjacent surfaces may cause one surface to lengthen appreciablymore than the adjacent surface or element.

One example of an expansion plate developed to accommodate this problemwhere air-tight connections are required is disclosed In U. S. Pat. No.3,343,327 to Konrad S. Svendsen for Expansion Plate. In the Svendsenpatent an expansion plate was provided having one or more panels, someof which comprised a plurality of adjoining cup-shaped members inside-by-side welded relation. The cups of these panels are deformed byopposed relative forces on opposite longitudinal edges of the panel ofwhich they are a part. Deformation of the cups allows an overalldeformation of the panel to accommodate the force couple resulting fromsaid opposed forces and to allow relative longitudinal movement of theopposed edges.

While the multiple cup type of panel is generally satisfactory as anexpansion plate, it does have several drawbacks. The many adjacent cupsin a panel are formed in a rectangular grid and require welding to jointhem to one another in gas-tight relationship. In some instances thecups might be formed by welding wall portions to one another. Typicallya 3 foot by 4 foot (or 3 inch X 4 inch) panel might have to 50 or morecups requiring six to eight weld seams transverse to the longitudinalextent of the panel and two to six or more weld seams extendinglongitudinally of the panel. In order to obtain panels having asufficient number of cups to allow the required deformation of thepanel, it will be evident that considerable time consuming and expensivewelding is required, some under difficult manufacturing conditions.

Further, each weld seam exhibits discontinuities caused by projections,irregularities and flaws in the formation of the weld. Suchdiscontinuities, as is well known, create weak spots at which cracks mayoriginate. These cracks may become sufficiently large to allow gasleakage. Such cracks may originate from thermal or pressure stressing ofthe region, as might normally occur during operating cycles. While suchdiscontinuities might be reduced in number or removed as by great carein welding or through subsequent machining, these operations are timeconsuming and expensive.

Other expansion joints have employed bellows-like members; however,these bellows have typically included a large number of weld seams intheir formation and particularly in regions thereof which are difficultto machine, thereby allowing the unwanted discontinuities.

SUMMARY OF THE INVENTION According to the present invention, anexpansion plate or sheet is provided which comprises a plurality ofpanels in sealed side-by-side relation, each panel including sheetswhich extend continuously substantially the full distance between twoadjacent walls for con nection in airtight relationship therewith andmost of said panels including at least one elongated depression thereinwhich extends much of the distance between the two adjacent walls.

The elongated depression in each panel is formed by a die-stamp ordrawing process which results in a smooth continuous surfacesubstantially devoid of discontinuities. Each depression is preferablyseveral times longer than wide and more than 1% times as deep as widealong most of its length. This configuration readily permits deformationof the panels through shear deformation of the depressions when oppositelongitudinal forces are applied to the opposite longitudinal edges ofthe panels, as through different expansions of the adjacent wall edges.The expansion plate formed by the above-described panels includes weldseams only extending parallel the depressions, and accordingly,transverse to the edges of the adjacent walls to which the panels arejoined.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic outline of a steamgenerator and furnace in which this invention finds particularapplication.

FIG. 2 is a detailed cross-section on line 22 of FIG. 3 of the plate andpanel connection and geometry according to the invention.

FIG. 3 is a side view of an assembled wall comprising panels of platesconnecting a steam header and an ash hopper of a steam generator.

FIG. 4 is a cross-section of a panel depression taken along line 4-4 ofFIG. 3.

FIG. 5 is an enlarged side view somewhat exaggerated of a corner of adistorted wall.

FIG. 6 is an enlarged top view of the corner shown in FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, atypical steam generator is diagrammatically illustrated in FIG. 1 toshow one application of the invention and comprises a furnace 10 havinga combustion chamber 12 defined by parallel, vertically extended weldedtogether tubes 16 forming the furnace walls and a portion of the gaspass 36 and adapted to have water forced therethrough for conversioninto steam. The water is fed by feedwater pumping, not shown, intoheaders such as 18, 20 and 22 and forced upward through the tubes 16into a header 24 and thence into a steam drum 26 in a well known manner.Steam is separated from the water in the drum 26 and is lead through thepipes 28 to the header 30 and tubes 32 to a header 34 from which it maybe fed to additional superheaters, not shown, and

thence to the point of consumption, not shown. It will be noted that thegases from the combustion chamber 12 pass upward and then laterallythrough a horizontal gas pass indicated generally at 36 thence through adownwardly directed gas pass 38 into a soot or ash hopper 40 and outthrough a duct 42 to the usual stack.

It is necessary that the gas pass andin fact the entire furnace fromcombustion chamber to stack be maintained as an air-tight ductparticularly where the furnace and combustion chamber is operated at anelevated pressure, or pressurized. One such point along the gas passthat must be kept air-tight is the connection between the steam or waterheader 34 and the walls of the ash hopper 40. The header 34 is steam orwater cooled while the walls of the ash hopper are subjected to the fulltemperature of the combustion gases passing through the-hopper on theway to the stack and hence are raised to a temperature somewhat higherthan the steam or water cooled header 34. The difference in temperaturesat the two adjacent surfaces of header 34 and ash hopper 40 subject themeach to different amounts of expansion.

In furnace construction itis usual to suspend the entire furnaceincluding all of the walls from overhead as by beams 44 and rods 46supporting the header and the tubes connected therewith. As will beexplained in more detail later, the walls of the ash hopper 40 aresuspended from the header 34 and being subjected to a higher operatingtemperature than the header 34 will expand to make the perimeter of theash hopper considerably greater than the perimeter of the header 34.Applicants expansion plate is used to connect and form an air-tightconnection between the header 34 and the walls of the hopper 40 and isshown somewhat schematically and diagrammatically at 48 in FIG. 1.

In order to more fully explain the invention, the details of thestructure at 48 connecting the header 34 with the walls of the hopper 40are illustrated and explained. This explanation will make it adequatelyclear how this construction can be used to connect these and othersimilar adjacent surfaces.

FIG. 2 shows a section of the header 34 and wall 52 of the hopper 40.The wall 52 is secured in any suitable manner as by welding to astructural member, such as channel iron 54 which is suspended from theheader 34 by straps 56 and pin joints 58. The upper edge of wall 52,which might also be a non-integral extension of hopper 40, is receivedbetween and forms a slip joint with a pair of spaced plates 60 securedin any suitable manner as by welding to the header 34. A plate,indicated generally at 62, and including the subject of this inventionis positioned outside of the hopper 40 and has one longitudinal edgesecured in any suitable manner as by welding to the header 34 and theopposite longitudinal edge secured in any suitable manner, preferablybywelding, to the channel 54 supporting the hopper walls.

The walls formed by plate 62 extend around the four sides of rectangularhopper 40 and forms an air-tight connection between the hopper and theheader 34. It will be appreciated that the tubes leading verticallyupward from the header 34 are welded together to form the duct definingthe gas pass 38 or other suitable means are provided to define that gaspass terminating in the header 34.

FIG. 3 is a side view of one-half of the ash hopper which may be 70 ormore feet across and shows portions of one-half of the plate 62extending along that side, with the center line of the plate shown atthe extreme left hand edge of the figure being taken as a portion of thehopper that has no relative longitudinal movement with respect to theheader 34 so that the hopper is substantially fixed longitudinally ofthe header 34 at this point but expands so as to move longitudinallyoutward of the header 34 at the comer of the hopper. Hence, all fourcorners of the hopper will move outwardly with respect to therectangular header 34.

It will be noted that the plate 62 is made up of a plurality ofindividual panels such as 64, 65, 66 and 68 and 69 among others. Thesepanels are arranged in a row with their adjacent vertically extendingedges secured together and together form the plate 62. As there issubstantially no relative movement of the hopper wall longitudinally ofthe pipe forming the header 34 adjacent the center line of the hopperside wall, the panel 64 is a plain rigid sheet having one edge welded tothe header 34 and the other edge welded to the channel iron 54.

As was described in the earlier-mentioned Svendsen patent, relativelongitudinal movement of the plate 62 increases away from the centerline of the hopper side wall as one moves toward the end of the plate62. The Svendsen patent accommodated thisrelative longitudinal movementby forming the various panels which make up plate 62 of deformablesheets having many cup-like depressions therein which increase in numberthe more distant the panel is from'the center line of the hopper'sidewall. In the present expansion plate the panels are also designed toaccommodate the increasing relative longitudinal movement; however,these panels preferably, though not necessarily, are uniform with theexception of panel 64 and more importantly are designed such that theygreatly reduce the opportunity for discontinuities in their structure,as for instance from irregular welds. Each of the present panelsbeginning with 65 and continuing on through panels 68 and 69 areconstructed to permit relative movement of the upper and lower edges ofplate 62 by allowing the sheet of the respective panel to torsionallydistort under shear forces to accommodate such relative movement.

A partial view of the torsionally distorted sheet with the distortionsomewhat exaggerated to more clearly illustrate the same is shown inFIG. 5. The relative longitudinal movement of header 34 and channel 54produces a force longitudinally of one edge of the plate 62 and aparallel force in the opposite direction longitudinally of the oppositeedge of the plate 62. The spacedapart non-intersecting forces produce aforce couple which is absorbed by shear deformation of the sheets of theseveral panels 65 through 71 which amounts to shear deformation of theplate 62.

- As earlier mentioned, panel 64 is a plain rigid sheet.

The remaining panels, moving or looking toward a corner, and includingpanels 65, 66, 68 and 69 each are comprised of a rectangular sheet 72 ofmetal, such as 12 gauge steel. Typically, a sheet 72 will be about 8inches in width longitudinally of plate 62 and some 20 to 36 inches inlength transversely of the plate. Each sheet 72 is intended to distortwith the relative opposing forces applied to the opposite longitudinaledges thereof during expansion of header 34 and hopper wall 52.

Each sheet 72 of the panels 65-69 includes an elongated trough-likedepression 74 therein which accommodates the shear forces at theopposite longitudinal edges of the sheet by allowing shear deformationof the sheet. Depression 74 extends preferably nearly the entirevertical, or transverse, exteng of a sheet 72 along the mid-line thereofand may be some 18 to 36 inches in length. The greatest width ofdepression 74 occurs at its lip and is on the order of 1% to 2% inchesas indicated by w in FIG. 4. This width is maintained for most of thelength of depression 74. The depth of depression 74 indicated as d inFIG. 4 is about 4 to 5 inches over most of the length of the depression.The width and depth of depression 74 are both decreased in a smooth andcontinuous manner over the final several inches at each end thereof toclose the ends of the depression. These end closures appear somewhatlike a bulletnose or rather half of a bullet-nose as divided by a planeon the axis of the bullet.

Depression 74 is formed in sheet 72 by means of a multi-stage drawingprocess. Several dies of increasing depth and slightly increasing widthand length are employed. The sheet 72 is placed sequentially in each dieand depression 74 is partially drawn on each, with an intermediate heattreatment of the sheet occurring between successive drawing operations,as required. Such heat treatment for stress relief would normally beperformed on stainless steel and not on carbon steel. The dies areshaped such that the final resulting depression 74 is somewhat wider atits lip or base than at the peak and, as mentioned earlier, shallows atits ends. The contour of depression 74, both internally and externally,is smooth and continuous, employing rounded surfaces where transitionsin slope or direction are required. The thickness of the walls of adepression 74 of the size and geometry described hereinbefore willtypically be at least 65 percent or more of the original thickness ofsheet 72, providing adequate strength to the depression. Any distortionof the edges of sheet 72 due to the stamping operation is corrected bytrimming and sizing the edges to provide the desired rectilinear formand size.

The above-described forming process and the resulting sheet 72 withdepression 74 provide a member which is capable of shear distortion toaccommodate the described growths but which is free of welds and thediscontinuities often engendered thereby;

In order to form expansion plate 62, a series of panels 65, 66, etc.,are joined to one another in side-by-side air-tight relationship as bywelds 76. Welds 76 occur between and along transversely extending edgesof adjacent abutting sheets 72. Welds 76 are thus transverse to thelongitudinal edges of the panels and expansion plate 62. Welds 76comprise substantially the only major welds in sheet 62 except at ornear the transverse extremes thereof. Panel 65 will be joined with rigidpanel 64 by a similar transversely extending seam weld.

"Panels 65, 66, etc., may each be installed separately in the field;however, it has generally proven more efficient and economical toweldingly join several panels in side-by-side relationship at the timeof manufacture to form major panels which may be to feet in longitudinalextent. The major panels are in turn joined to one another in the fieldby field welds 78 along transversely extending adjacent edges of themajor panels.

The longitudinally extending upper edge portion of each sheet 72 andaccordingly of each panel 64, 65, 66 etc., is welded in air-tightrelation to a strip 80 which extends longitudinally along header 34 andis welded thereto in air-tight relation'therewith. Each sheet 72 ismounted such that the depressions 74 extend outward from gas pass 38.The opposite edge portion of each sheet 72 is secured in air-tightrelationship as by welding to a double bent, or open U-shaped, metalstrip 82 which in turn is secured as by welding with channel 54 to forman air-tight connection therebetween. Double bent strip 82 allows alimited degree of vertical, or transverse, movement of the sheets 72relative to ash hopper 40 if such is needed. Strip 82 may be consideredeither as a portion of each panel 64, 65, 66 etc., as joined theretoduring manufacturing or as a portion of ash hopper 40 which aids injoining the panels thereto during field installation. Preferably, strip82 will be joined to the lower edge of the several sheets 72 whichcomprise a major panel at the time of manufacture.

In order to prevent the flexible sheets 72 forming the panels 65, 66,etc., from bulging from the pressure in gas pass 38, a channel iron 84or another type such structural member is supported against the outsideof plate 62. Channel irons 84 are positioned at various locations alongplate 62 intermediate various adjacent pairs of depressions 74 and areretained by means of a clip 86 welded to strip at one end of the channel84 and a clip 88 welded to the channel 54 at the other end of channel84.

Where expansion plate 62 encounters a corner as in FIG. 6 it iscomprised of several panels such as 70, 71, 73 and 75 which arecomprised of sheets 72 and depressions 74 identical to those in panel 65with the exception that their sheets 72 are longitudinally curved,rather than flat, such that the several sheets in side-byside weldedrelation complete a 90 bend. Typically, the panels containing thesecurved sheets, for instance 70, 71, 73 and 75, are weldingly joinedside-by-side at manufacture to form a major panel and are field weldedto adjacent panels in the field. A corner seal plate 90 may be used ateach comer to sealingly connect as by welding the upper longitudinaledges of panels 70, 71, 73 and 75 with the header 34 to insure anair-tight seal along the entirety of plate 62.

. FIGS. 5 and 6 show, somewhat exaggerated, how the flexible platedistorts to accommodate the difference in longitudinal expansion in theelements it connects. The longitudinal movement of the expansion isabsorbed by the longitudinal movement of one edge of the flexible sheetrelative to the other under the shear forces imposed by the expansion.The depressions or troughs 74 skew somewhat from a vertical orientationto one in which that portion nearest header 34 moves relativelylongitudinally toward the center line of hopper 52 and the portionnearest hopper 40 moves relatively longitudinally toward the corner. Atthe corners, the portion of depression 74 nearest header 34 movesrelatively inward toward the center line of gas pass 38 and the otherend moves relatively outward therefrom. Little or no longitudinalskewing occurs right at the corners, but the longitudinal shear forcesdeveloped along the side walls causes shear distortion of the panelwhich increases in magnitude near the corners. While the number orfrequency of occurrence of depressions 74 might be decreased nearer thecenter line of hopper wall 52, it has been found desirable byexperimentation to use a uniform panel member with a single depressionfor every one of the panels from 65 outward to the comer.

The shear forces which skew depressions 74 accordingly distort or skewthe panels themselves. This distortion of the depressions accommodatesor allows this deformation of the panels to occur without damage to thepanels. Additional torsional distortion of depressions 74 about an axisrunning the length thereof has also been noted. The relatively greatdepth-to-width ratio of the depressions is felt to aid in thedeformation process, particularly along the sides of plate 62 near thecorner where the opposed longitudinal forces are greatest.

While for the purpose of illustration and explanation the connectingplate has been described in detail as the connection between a steamheader and an ash hopper subject to different operating temperatures andhence to different amounts of expansion, it will be understood that theinvention is not limited to such structure, however, and that thisinvention may be used as a means for connecting other elements subjectto limited relative movement particularly where that relative movementis occasioned by temperature differences and it is desired to have theconnection form an air-tight connection between the two elements.

What is claimed is:

l. Means forming an air-tight connection between two adjacent sectionsof a gas pass wall, which sections have different relative operatingtemperatures comprising an elongated imperforate plate, edge weldedairtight to and connecting said sections and forming a portion of saidwall, said plate comprising a series of transversely extending panelseach welded in side-by-side arrangement, the panel at a selectedlongitudinal portion of said plate comprising a substantiallyundistortable plain sheet and the remaining panels intermediate saidselected portion and one end of said plate each comprising a continuoussheet extending substantially the entire transverse extent of said paneland having a depression therein extending most of the transverse extentthereof, whereby to absorb a force couple on said plate by sheardeformation of said depressioncontaining panels.

2. An air-tight connection connecting adjacent walls of two abuttingducts, said ducts having adjacent edges subject to relative movementlongitudinally of said edges and producing a change in the relativeperimeter of said abutting ducts, said connection comprises animperforate plate extending continuously substantially the entiredistance between said abutting ducts and ineluding elongated depressionstherein extending substantially the full extent thereof transverse tothe adjacent edges of said abutting ducts, means connecting one edge ofsaid plate in an air-tight manner with one wall of one duct to form anintegral extension of said duct wall and to apply forces in onedirection longitudinally of one edge, and means connecting the oppositeedge of said plate in an air-tight manner with the adjacent wall of theother duct to form an integral extension of said adjacent wall and toapply forces in the opposite direction lengthwise of said opposite edge,said plate being distortable by said forces and the relativelongitudinal movement of said adjacent edges, said connectionaccommodating said relative movements of said adjacent duct walls byshear distortion of said plate.

3. Means as claimed in claim 2 wherein said imperforate plate includes aplurality of panels, each panel extending continuously substantiallyentirely between said abutting ducts and joined in air-tightside-by-side relationship by weld seams extending only substantiallyparallel said elongated depressions transversely of the adjacent edgesof said abutting ducts and each said panel includes a said elongateddepression therein.

4. A torsionally distortable panel for connecting two adjacent members,which members are subject to movement longitudinally of the panel edge,said panel including a continuous sheet extending transverselysubstantially the entire transverse extent of said panel and having anelongated depression therein extending most of the transverse extent ofsaid sheet, first means for connecting one edge of said panel with oneof said adjacent members and second means for connecting the oppositeedge of said panel with the other said adjacent member, said edgeconnecting means adapted to transmit the relative longitudinal movementof said members, and the resulting force couple, longitudinally to theopposite edges of said sheet, said sheet being deformable by saidtransmitted relative longitudinal movement, cause a skewing andtorsional bending of said depression.

5. Means as claimed in claim 4 wherein the depth of said depression overmost of its length is at least 1.5 times its width thereat.

'6. Means as claimed in claim 5 wherein the length of a said depressionis more than twice the width of said depression.

1. Means forming an air-tight connection between two adjacent sectionsof a gas pass wall, which sections have different relative operatingtemperatures comprising an elongated imperforate plate, edge weldedair-tight to and connecting said sections and forming a portion of saidwall, said plate comprising a series of transversely extending panelseach welded in side-by-side arrangement, the panel at a selectedlongitudinal portion of said plate comprising a substantiallyundistortable plain sheet and the remaining panels intermediate saidselected portion and one end of said plate each comprising a continuoussheet extending substantially the entire transverse extent of said paneland having a depression therein extending most of the transverse extentthereof, whereby to absorb a force couple on said plate by sheardeformation of said depression-containing panels.
 2. An air-tightconnection connecting adjacent walls of two abutting ducts, said ductshaving adjacent edges subject to relative movement longitudinally ofsaid edges and producing a change in the relative perimeter of saidabutting ducts, said connection comprises an imperforate plate extendingcontinuously substantially the entire distance between said abuttingducts and including elongated depRessions therein extendingsubstantially the full extent thereof transverse to the adjacent edgesof said abutting ducts, means connecting one edge of said plate in anair-tight manner with one wall of one duct to form an integral extensionof said duct wall and to apply forces in one direction longitudinally ofone edge, and means connecting the opposite edge of said plate in anair-tight manner with the adjacent wall of the other duct to form anintegral extension of said adjacent wall and to apply forces in theopposite direction lengthwise of said opposite edge, said plate beingdistortable by said forces and the relative longitudinal movement ofsaid adjacent edges, said connection accommodating said relativemovements of said adjacent duct walls by shear distortion of said plate.3. Means as claimed in claim 2 wherein said imperforate plate includes aplurality of panels, each panel extending continuously substantiallyentirely between said abutting ducts and joined in air-tightside-by-side relationship by weld seams extending only substantiallyparallel said elongated depressions transversely of the adjacent edgesof said abutting ducts and each said panel includes a said elongateddepression therein.
 4. A torsionally distortable panel for connectingtwo adjacent members, which members are subject to movementlongitudinally of the panel edge, said panel including a continuoussheet extending transversely substantially the entire transverse extentof said panel and having an elongated depression therein extending mostof the transverse extent of said sheet, first means for connecting oneedge of said panel with one of said adjacent members and second meansfor connecting the opposite edge of said panel with the other saidadjacent member, said edge connecting means adapted to transmit therelative longitudinal movement of said members, and the resulting forcecouple, longitudinally to the opposite edges of said sheet, said sheetbeing deformable by said transmitted relative longitudinal movement,cause a skewing and torsional bending of said depression.
 5. Means asclaimed in claim 4 wherein the depth of said depression over most of itslength is at least 1.5 times its width thereat.
 6. Means as claimed inclaim 5 wherein the length of a said depression is more than twice thewidth of said depression.